Contact plug



Feb. 20, 1940.

W. P. HERMAN CONTACT PLUG Filed April 11-, 1956 Patented Feb. 20, 1940 William P. Herman,

Electrix ('Jorporation Island s PATENT OFFICE CONTACT PLUG Providence, R. L, assignor to a corporation of Rhode Application April 11, 1936, Serial No. 73,901 7 Claims. (01. 173-361) My present invention relates to the manufacture of electrical fixtures and has particular reference to a novel co nstruction for contact It is a principal object of my invention to @devise a contact plug con contact blades may by insertion from the neck.

It is a further vise .a plug construction any tendency to short struction in which the be locked into the plug body bject of attached to the contact blades.

It is an additional object of provide a contact blade which insertion and my invention to dewhich will eliminatecircuit between the wires my invention to will facilitate the securing of the wire ends thereto.

It is an additional object of my invention to simplify the manufacture o f the plug body.

Another object of my invention is to provide structures for the blades that 'will facilitate .assembly body and the contact of the parts.

With the above and other objects and advantageous features in view, sists of a novel arrangemen disclosed in the det conjunction with pended thereto.

In the drawing,

my invention cont of parts more fully ailed descriptidn following, in the accompanying drawing, and more specifically defined in the claims ap- Flg. 1 is a perspective view of the novel contact plug;

Fig. 4 is a bottom Fig. 5 is a perspective vi contact blades prior to assembly;

of insertion of the contact blades;

Fig. ,7 is a perspec plug, parts being broken away ing engagement of rangement of the body has been found contact plug in whi through the neck of the plug body against by no parts of the as'se plan view of the plug body; at! showing the novel Fig. 6 is a sectional view showing the method tive view of the assembled to show the lockthe blades in the body; and

Fig. 8 is a perspective view showing the ardie parts for producing the desirable to manufacture a oh the blades are inserted the plug and are locked in accidental removal, wherembly are exposed to view,

and no end washers or discs are necessary. To

a plu dy this. end I have devised a novel manufacture for which provides lock landings for locking the contact blades in position when the blades. are assemble have improved the simplify the assembling a wires thereto. Moreover,

lug body that the part of the body circuiting between (1 from the neck end, and I blade construction so as to nd securing of the lead I have so formed the lead wires are separated by interior so as to eliminate sho the lead wires.

Referring to the drawing, the novel contact plug 10 is shown in perspective in Fig. 1- andineludes two contact blades ll rounded or shaped at their ends in the usual manner to facilitate entrance into the contact socket slots. The contact plug includes a plug body l2, 3, which has a neck It having a central opening it, the body'being shaped to provide two diverging passageways extendingdownwardly through the plug body. Each passageway comprises an upper channel portion l5 communicating with a lower fiat blade receiving slot portion, the slot portion having its walls extending laterally toward each other to form a restricted passage l6 which terminates in a wider endslot H; the passage walls being provided with lock" shoulders or landings l8 and I9 for a purpose hereinafter to be described.

. Referring now to Fig. 5, two contact blades ll of metal, such as brass, each having a reduced portion conforming in shape with the restricted passage I6 and having shoulders 20a for con-. tact with the shoulders or landings l8 and I9, and having a head portion 2|, each provided with a transverse slot 22. The cord 23 has the usual insulated lead wires 24, the'ends of which when stripped of. insulation may be readily inserted through the slots 22 and turned over and molded, dipped or soldered in place, the assembly operation thus being greatly simplified. With the parts assembledas shown in Fig.

. theparts may then be inserted into the plug bodyas disclosed in Fig. 6, the ends of the blades I! being forced downwardly through the restricted passages l6, which give, as the plug body, is preferably made of a flexible insulated material such as soft rubber, and then return to lock the blades in place as indicated in Fig. 7, the shoulders or landings l8 and I9 firmly looking each blade against accidental removal from the plug base, and interposing a strong resistance to intentional removing.

The manufacture of the novel plug body is greatly simplified by using dies of the type shown in Fig. 8, comprising a bifurcated upper die 25 and a lower die 26 which has spaced upstanding portions 21 terminated in reduced portions 28, whereby the plug body may be readily molded, the dies then being removedby moving in opposite directions. The improved construction therefore includes a novel plug body which has separated passageways for each blade and its wire, the space between the passageways being in the form'of an insulating cone 29, see Fig. 2, thus eliminating short circuiting between the ends of the two wires. The two wires are readily assembled to the blades by use of the transverse slot described and illustrated, which eliminates any need for passing the wire end through blade opening, as has been standard practice see Figs. 2 and,

heretofore, as the wire ends are readily slipped into the slot, and the landings formed at the ends of the restricted passages it effectively prevent accidental removal ofthe blades from the plug body. The blades remain in the plug body without any distortion of the rubber,'whereby there is no tendency to decrease the resilience or the effective life of the base as the result of internal strain, and there are no exposed connecting parts, whereby no insulating washers such as hitherto employed are required.

The preliminary securing of the wire ends to the blades permits a quick assembly into the plug body, which may be a hand or preferably a machine assembly, whereby the manufacturing cost is-greatly reduced. 7

The conical insulating section has an important advantage in use, in that the resilient plug body cannot be squeezed by the user so as to move the lead wires or the blade inner ends towards each other so as to produce a short circuit. The

plug body is preferably molded in one piece, but

may, if desired, be of two or three'piece construction. Moreover, although the passageways are 'disclosed as having reduced sections, providing landings engaged by the blade shoulders, the construction of the parts can be reversed, the passageways having enlarged sections or wall recesses, by using collapsible cores, or by having sufllciently resilient rubber material; the blades are formed with corresponding intermediate portions.f

Although I have described the plug body as made of molded rubber, it may be made of any insulating material having the same properties;

if desired, the blades may be directly locked to the body by molding the body around them.

While I have described a specific constructional embodiment of my invention and specific formations for the plug body, any desired changes in the material used for the parts, in their relative arrangement and assembly and in their relative proportions may be. made to suit the requirements for different contact plug designs, without departing from the spirit and scope of the invention as defined in the appended claims.

I claim: 1. In a contact plug, a one piece base of resilient flexible material having an upper central recess .andtwo passageways diverging downwardly therefrom and extending through the plug, said base having integral spaced parallel portions in .each passageway extending towards each other to form restricted passages intermediate the ends of said passageways, and straight contact blades the blades engaging the parallel portions, the upper ends of said blades extending into the upper portions of said passageway said upper ends having transverse slots for connecting the cord lead wires.

2. In a contact plug, a one piece base of resilient flexible material having an upper central recess" and two passageways comprising flat slots diverging downwardly therefrom and extending through the plug, said base having integral spaced separate parallel portions in each slot extending towards each other to form restricted passages intermediate the ends of said slots, and straight flat contact blades seated in said slots and having recessed portions in the blades engaging the parallel portions, the upper ends of said blades extending into the upper portions of said passageways, said upperends having means for connecting cord lead wires thereto.

3. In a contact plug, a one piece base of resilient flexible material having an upper central recess adapted to receive a cord and two passageways comprising flat slots diverging downwardly therefrom and extending through the plug, said base having integral spaced separate parallel portions in each slot extending towards each other to form restricted passages intermediate the ends of said slots, and straight flat contact blades seated in said slots, said blades having reentrant portions adapted to receive said projecting parallel portions in said slots.

4. Ina contact plug, a one piece base of resilient flexible material having an upper central recess adapted to receive a cord and two passageways comprising flat slots diverging downwardly therefrom through the plug, the body of said plug between said passageways tapering into said upper central recess to form an insulating core adapted to dielectrically separate the ends of the cord wires, said base having integral spaced separate portionsin each slot projecting towards each through the plug, said base having integral spaped parallel portions in each slot extending towards each other to form restricted passages in said slots, and straight contact blades seated in said slots having recessed portions engaging the parallel portions, the upper ends of said blades extending into the upper portions of said passageways, said blades having transverse slots for connecting cord lead wires thereto.

6. In a contact plug, a one piece base of resilient flexible material having an upper central recess and two passageways comprising flat slots diverging downwardly therefrom and extending through the plug; said base having integral spaced separate parallel portions in each slot extending towards each other to form restricted 7. In a contact plug, a one-piece base of resilient flexible material having an upper central recess adapted to receive a cord and two passageways diverging downwardly and comprising flat slots extending through the base, the body of said plug between said passageways tapering into said upper central recess to form an insulating baille adapted to dielectrically separate the ends of the cord wires, one wall or each slot having a portion projecting towards the opposite wall 01 the slot in parallel relation thereto to form a restricted passage having end thereof, and flat contact blades seated in said slots and having integral cooperating lock parts engaging said lock shoulders.

WILLIAM P. HERMAN.

v said blades having.

means for connecting cord lead wires thereto. seated in said passageways, recessed portions in lock shoulders at each 

